bus: mhi: core: Indexed MHI controller name

Today the MHI controller name is simply cloned from the underlying
bus device (its parent), that gives the following device structure
for e.g. a MHI/PCI controller:
devices/pci0000:00/0000:00:01.2/0000:02:00.0/0000:02:00.0
devices/pci0000:00/0000:00:01.2/0000:02:00.0/0000:02:00.0/0000:02:00.0_IPCR
...

That's quite misleading/confusing and can cause device registering
issues because of duplicate dev name (e.g. if a PCI device register
two different MHI instances).

This patch changes MHI core to create indexed mhi controller names
(mhi0, mhi1...) in the same way as other busses (i2c0, usb0...).

The previous example becomes:
devices/pci0000:00/0000:00:01.2/0000:02:00.0/mhi0
devices/pci0000:00/0000:00:01.2/0000:02:00.0/mhi0/mhi0_IPCR
...

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>

4 files changed, 20 insertions, 4 deletions

diff --git a/drivers/bus/mhi/core/debugfs.c b/drivers/bus/mhi/core/debugfs.c
index 7d43138ce66d..858d7516410b 100644
--- a/drivers/bus/mhi/core/debugfs.c
+++ b/drivers/bus/mhi/core/debugfs.c
@@ -377,7 +377,7 @@ static struct dentry *mhi_debugfs_root;
 void mhi_create_debugfs(struct mhi_controller *mhi_cntrl)
 {
 	mhi_cntrl->debugfs_dentry =
-			debugfs_create_dir(dev_name(mhi_cntrl->cntrl_dev),
+			debugfs_create_dir(dev_name(&mhi_cntrl->mhi_dev->dev),
 					   mhi_debugfs_root);
 
 	debugfs_create_file("states", 0444, mhi_cntrl->debugfs_dentry,
diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
index c5fe0be7c022..96cde9c0034c 100644
--- a/drivers/bus/mhi/core/init.c
+++ b/drivers/bus/mhi/core/init.c
@@ -8,6 +8,7 @@
 #include <linux/device.h>
 #include <linux/dma-direction.h>
 #include <linux/dma-mapping.h>
+#include <linux/idr.h>
 #include <linux/interrupt.h>
 #include <linux/list.h>
 #include <linux/mhi.h>
@@ -18,6 +19,8 @@
 #include <linux/wait.h>
 #include "internal.h"
 
+static DEFINE_IDA(mhi_controller_ida);
+
 const char * const mhi_ee_str[MHI_EE_MAX] = {
 	[MHI_EE_PBL] = "PBL",
 	[MHI_EE_SBL] = "SBL",
@@ -940,6 +943,12 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl,
 	mhi_cntrl->minor_version = (soc_info & SOC_HW_VERSION_MINOR_VER_BMSK) >>
 					SOC_HW_VERSION_MINOR_VER_SHFT;
 
+	mhi_cntrl->index = ida_alloc(&mhi_controller_ida, GFP_KERNEL);
+	if (mhi_cntrl->index < 0) {
+		ret = mhi_cntrl->index;
+		goto error_ida_alloc;
+	}
+
 	/* Register controller with MHI bus */
 	mhi_dev = mhi_alloc_device(mhi_cntrl);
 	if (IS_ERR(mhi_dev)) {
@@ -950,8 +959,8 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl,
 
 	mhi_dev->dev_type = MHI_DEVICE_CONTROLLER;
 	mhi_dev->mhi_cntrl = mhi_cntrl;
-	dev_set_name(&mhi_dev->dev, "%s", dev_name(mhi_cntrl->cntrl_dev));
-	mhi_dev->name = dev_name(mhi_cntrl->cntrl_dev);
+	dev_set_name(&mhi_dev->dev, "mhi%d", mhi_cntrl->index);
+	mhi_dev->name = dev_name(&mhi_dev->dev);
 
 	/* Init wakeup source */
 	device_init_wakeup(&mhi_dev->dev, true);
@@ -970,6 +979,9 @@ error_add_dev:
 	put_device(&mhi_dev->dev);
 
 error_alloc_dev:
+	ida_free(&mhi_controller_ida, mhi_cntrl->index);
+
+error_ida_alloc:
 	kfree(mhi_cntrl->mhi_cmd);
 
 error_alloc_cmd:
@@ -1004,6 +1016,8 @@ void mhi_unregister_controller(struct mhi_controller *mhi_cntrl)
 
 	device_del(&mhi_dev->dev);
 	put_device(&mhi_dev->dev);
+
+	ida_free(&mhi_controller_ida, mhi_cntrl->index);
 }
 EXPORT_SYMBOL_GPL(mhi_unregister_controller);
 
diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index 80d1580bda13..6959939b88d1 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -350,7 +350,7 @@ void mhi_create_devices(struct mhi_controller *mhi_cntrl)
 		/* Channel name is same for both UL and DL */
 		mhi_dev->name = mhi_chan->name;
 		dev_set_name(&mhi_dev->dev, "%s_%s",
-			     dev_name(mhi_cntrl->cntrl_dev),
+			     dev_name(&mhi_cntrl->mhi_dev->dev),
 			     mhi_dev->name);
 
 		/* Init wakeup source if available */
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index 56ff1eca6684..5721a0ab1ddb 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -356,6 +356,7 @@ struct mhi_controller_config {
  * @read_reg: Read a MHI register via the physical link (required)
  * @write_reg: Write a MHI register via the physical link (required)
  * @buffer_len: Bounce buffer length
+ * @index: Index of the MHI controller instance
  * @bounce_buf: Use of bounce buffer
  * @fbc_download: MHI host needs to do complete image transfer (optional)
  * @pre_init: MHI host needs to do pre-initialization before power up
@@ -446,6 +447,7 @@ struct mhi_controller {
 			  u32 val);
 
 	size_t buffer_len;
+	int index;
 	bool bounce_buf;
 	bool fbc_download;
 	bool pre_init;